What science says about the health benefits of yoga

Yoga is no longer considered a fringe activity in Western society, but rather so much a part of mainstream culture today that major medical centers, community healthcare centers, and neighbourhood yoga studios offer yoga as a mind-body practice to support health and healing. Although yoga has existed in various forms for around 2,500 years, the phenomenon of “yoga for health” is a characteristic of more modern yoga.

While scientific research on the health effects of yoga postures has been conducted and published for many years, this line of scientific inquiry has grown tremendously only in the last ten to 20 years, especially in terms of more rigorous randomised, controlled trials (RCT). In addition to RCTs of the health benefits of yoga, there are many other important avenues of yoga research such as epidemiological research that helps researchers to understand the characteristics of people who practice yoga, methodological and measurement research to improve the quality of yoga research, and qualitative yoga research with narratives that directly carry the voices of those who teach and practice yoga. There has also been considerable research done on the more general physical effects of yoga practice. With this large upsurge in research documenting the therapeutic effects of yoga, efforts have been underway to understand the mechanisms of these health benefits, including research on inflammation and the autonomic nervous system.

While most yoga research has been conducted on adults, there is increasing interest in the benefits of yoga on a more complete span of individuals - including school age children, adolescents, expectant mothers, and the elderly. Yoga research is quickly being extended to other populations as well, including people in the workplace, among athletes, and a strong new interest in yoga research among active duty military and veterans with pain conditions, combat stress and Post Traumatic Stress Disorder (PTSD).  

With the emergence of higher quality yoga research, there is evidence that yoga has sizable and replicable effects for many health conditions. Although health is viewed as holistic in yogic traditions and aspects of health are clearly intertwined, research often targets specific areas such as physical health, mental health, and/or spiritual well-being. Some conditions that have been well studied include depression, stress and anxiety, irritable bowel syndrome, HIV, heart conditions, cancer, and chronic low back pain (CLBP). With CLBP, for example, a recent review documented consistent findings that yoga can improve function and decrease pain in people with CLBP. Additionally, yoga practice among people with CLBP reduces depression and pain medication use and improves quality of life.

The benefits of yoga for cancer survivors have been studied, with the majority of research focusing on alleviating symptoms of radiation or chemotherapy, such as fatigue. A recent review concluded that yoga improves quality of life and psychosocial outcomes including depression in cancer survivors, but evidence is limited for supporting improvements in fatigue or sleep.

In mental health, yoga has been shown to reduce stress and anxiety and depressive symptoms. In more severe depression where suicide is a major risk, yoga is best viewed as adjunctive to other treatments. The benefits of yoga for schizophrenia has been studied, with evidence of short-term improvements in quality of life and social functioning, however, we don’t know yet potential long-term benefits if any. The benefits of yoga for substance use and addictions is an area that appears promising, but more research is needed.

Considerable research has also been conducted examining the effects of yoga on cardiovascular risk factors, including a recent review concluding that yoga is a promising method for reducing high blood pressure (hypertension). Other reviews too report a variety of beneficial effects of yoga for cardiovascular diseases more broadly. For asthma, the breathing component of yoga has been linked to improvements in lung function, but has not proven to be better than standard breathing exercises for those specific outcomes.

There are findings from other health conditions that we could mention, however, these are from more pilot and/or smaller research studies and the results are considered more preliminary or inconclusive. This is not surprising, given it is only recently that adequate research funding has been available to conduct the larger, more rigorous scientific studies.

With few exceptions among all of the research that has been conducted, findings indicate that yoga rarely has harmful effects and is well received by participants. There may be certain poses or types of yoga that are not good for certain health conditions, and good research is done in collaboration with clinical experts and certified yoga instructors who can guide the choice of the style of yoga that will produce the most benefit. Like other exercise activity, the risks of injury from improperly performing yoga postures vary depending on how, where, and with whom the yoga is practiced. The initial practice of yoga under the direction of experienced yoga instructors is thus recommended, as is following a program that has been modified specifically for people with the afflicting health condition. For optimal safety, individuals with specific health concerns should consult their physician before starting a yoga program. While there have been media stories alerting people to the dangers of yoga, data from most research studies reveal very few serious adverse events. For example, in RCT studies of adults with CLBP taught by experienced yoga instructors, three serious adverse events were reported among 308 persons and each was related to herniated discs, and at least one of these was found to be unrelated to yoga practice. Disc problems are common in CLBP in the absence of yoga practice, and thus may have occurred just as readily with inactivity or other activity.

Clearly, in cases where yoga does not offer significant relief from physical disease, it can still offer some measure of relief from suffering. In this sense, yoga can provide a different way of looking at pain and suffering, which in itself can potentially alleviate some suffering. The basic realisation that “I” am not my body, or my thoughts, or my sensations of pain, is itself healing or liberative from a certain kind of existential suffering.

Finally, the original purpose of yoga – to increase one’s spiritual well-being or connection with the divine - has typically been a neglected area for researchers. The popularity of yoga as an exercise that is being done in health clubs has probably led to some de-emphasis of spirituality. We have seen a sort of translation of the spiritual system of yoga into a form of practice acceptable in a secular context, and an integral feature of yoga is that it adapts to each unique historical era and cultural context. While it is true that some people may be more likely to refuse to try yoga if spirituality is emphasized, it may be possible for the spiritual aspects of yoga to be woven in gently as a feature of yoga practice while emphasizing other physical and mental health benefits as described in this article. To this effect, one study found that the reasons for starting versus continuing yoga changes over time, becoming mostly a spiritual reason after a period of regular practice. Studies report that the practice of yoga enhances one’s spiritual well-being.

Erik J Groessl, PhD, Associate Professor of Family Medicine and Public Health; Director, UC San Diego Health Services Research Center.

Deepak Chopra, MD, Associate Clinical Professor of Family Medicine and Public Health, UC San Diego; Co-Founder, the Chopra Center for Wellbeing.

Paul J Mills, PhD, Professor of Family Medicine and Public Health; Director, Center of Excellence for Research and Training in Global Integrative Health, UC San Diego.